text: Her previous attempt to change the law was defeated in parliament but she said the public now had better awareness of the issue.
  The Lothians MSP, who has Parkinson's disease, outlined her Assisted Suicide Bill in Edinburgh.
  The Scottish government has said it does not support a change in the law.
  And it is still unclear whether there is majority backing for the measure among MSPs.
  The bill's strongest critics have said it could see Scotland becoming a "suicide tourism" destination, along with other countries where the practice is legal, such as Switzerland.
  There have also been concerns it could fail to safeguard frail, elderly people.
  Ms MacDonald told the BBC she had learned lessons from her previous attempt to get a bill passed and had brought forward a clearer and more straightforward process.
  Her bill would allow people whose lives became intolerable through a progressive degenerative condition or terminal illness to seek a doctor's help in dying.
  There are also a series of safeguards which aim to prevent abuse of the legislation.
  The main measures in the bill include:
  Ms MacDonald said: "I decided as soon as we lost the last one that I had to get a better one and reintroduce it, because so many people think this is the right thing to do for people who have a progressive, degenerative condition who are facing a less than dignified end.
  "And people who are terminally ill, if they want to go just a bit sooner, they should be able to choose to do so without making anyone subject to prosecution."
  In 2010, Ms MacDonald's End of Life Assistance Bill was defeated by 85 votes to 16, with two abstentions, by MSPs who were allowed a free vote on the legislation, rather than on party lines.
  But Ms MacDonald said she hoped high-profile cases such as that of Tony Nicklinson in England, who had locked-in syndrome and battled for years for a legal right to end his life, had increased awareness.
  And she pointed to last year's report from the Commission on Assisted Dying - set up and funded by campaigners who want to see a change in the law in England and Wales - which said the current system was "inadequate".
  Ms MacDonald said she was "pretty certain" support for her bill among MSPs had grown since 2010.
  Her new bill is launched a day after opponents of assisted dying from across Europe met to speak out against the move.
  The Euthanasia Prevention Coalition Europe, convened in Brussels, included the Scottish group Care Not Killing, an alliance of 50 groups, including faith-based organisations, which is strongly opposed to Ms MacDonald's proposals.
  It is not illegal to attempt suicide in Scotland, but helping someone take their own life could lead to prosecution.
  In England and Wales, the Suicide Act 1961 makes it an offence to encourage or assist a suicide or a suicide attempt, which is almost identical to the situation in Northern Ireland.
  The Director of Public Prosecutions has to approve any assisted suicide court action in England, Wales and Northern Ireland.
  In 2010, Keir Starmer, then the DPP, issued guidance that made it clear that family or friends who travelled with a loved one to the Swiss suicide group Dignitas would not risk prosecution.
  The guidelines were the result of a case brought by Debbie Purdy, a terminally ill woman, who in 2009 won a legal ruling requiring the DPP to set out whether her husband would be committing an offence if he accompanied her to Dignitas to end her life.
  Scotland's prosecution service, the Crown Office, has issued no such guidance.
  Assisted suicide is legal in Luxembourg, the Netherlands and Belgium as well as Switzerland.
  Q&A: Right-to-die debate
  Care Not Killing convener Dr Gordon Macdonald said: "The Scottish Parliament overwhelmingly rejected an attempt by Margo MacDonald to legalise euthanasia and assisted suicide in 2010.
  "MSPs concluded that vulnerable people would be put at risk from such legislation.
  "Scotland can learn from the damaging effects of legalising euthanasia and assisted suicide in other parts of Europe and North America.
  "Europe can learn from Scotland's example as a country which has rejected the view that some people's lives are not worth living. We believe that society has a responsibility to protect the most vulnerable."
  It is not illegal to attempt suicide in Scotland, but helping someone take their own life could lead to prosecution.
  The Suicide Act 1961 makes it an offence to encourage or assist a suicide or a suicide attempt in England and Wales, which is almost identical to the law in Northern Ireland.
  Outside Scotland, the Director of Public Prosecutions (DPP) has to approve any assisted suicide court action in England, Wales and Northern Ireland.
  In 2010, Keir Starmer, then the DPP, issued guidance that made it clear that family or friends who travelled with a loved one to the Swiss suicide group Dignitas would not risk prosecution.
  Ms MacDonald is pressing ahead with her fresh bill after getting the necessary 18 signatures from other MSPs to bring it to parliament.
  She is officially launching the legislation at an event in Edinburgh, along with MSPs representing all the political parties and Silvan Luley, of Dignitas.
  Assisted suicide is legal in Luxembourg, the Netherlands and Belgium as well as Switzerland.
  In the House of Lords, the Labour peer and former UK Lord Chancellor, Lord Falconer, has proposed a bill on legalising assisted suicide.
target: Proposals to give terminally ill people in Scotland the legal right to assisted suicide have been relaunched by the independent MSP Margo MacDonald.